Control device



July 23, 1935. F. A. PARSONS 2,008,769

. GONTR-OL DEVICE Filed Dec. 6, les 5 Sheets-Sheet 1 July 23, 1935;

F. A. PARSONS CONTROL DEVICE Filed Dec. 6, 1929 3 Sheets-Sheet 2 F. A. PARSONS 2,008,769-

CONTROL DEVICE July 23, 1935.

Filed Dec. 6, 1929 sweets-sheets Era-.5, 4

PEA-3.1085 4/116 72 3801.15 6W Patented July 23,- 1935 UNITED STATES PATENT OFFICE This invention relates to control devices -and more particularly to devices in which a power operated controller or shifter is actuated in substantially exact accordance with the movement of a master control which is itself free of load- A purpose of the invention is to provide control means in which a master controller may be moved by a relatively very weak force, yet may control the movement of devices or objects requiring relatively .very great force for their movement.

A further purpose is toprovide 'a control such as just mentioned, in which the device is so constructed that should the power for operation of the controller or shifter fail for any reason,;suc h force as may be available from the master controller is applicable for the desired movement of the part or thing to be moved. As an illustration, when the device is used for the power steering of an automobile or truck it is highly important that .the vehicle should be manually dirigible if i the pow'er device should for any, reason fail to operate; V V A further purpose is 'to provide a construction such that should the power for the controller or shifter for any reason fail the master controller is not only operative to directly control the: part or thing to be moved, but is movable in substantially the same manner or through substantially the same cycle of travel, so that for instance in ,the case of a' power steered vehicle, the operator isunder no necessity of shifting from one mode of operation toanother' in' the case of the failure of the power to'function properly. g A further purpose is-to provide a device which in eilfect amplifies the power of amaster controller and applies such amplified or increased power for the movement of the part or thing to be moved in exact accordancewith-themovement of the master controller.

Another purpose is to provide improved bydraulic or fluid means for accomplishing the above mentioned objects whereby'certain advantages inherent in hydraulically operated devices may be had. 1

Another object is to providean improved power operated system of vehicle control, :particularly for the steering gear and brakes of automotive vehicles such as trucksohpassenger vehicles, buses, tractors, etc. I V Another object is generally to simplify and improve the construction and operation of control devices for the above mentioned purposes and for still other purposes which 'will be apparent from this specification. V

The invention consists in the structure herein illustrated; described and claimed, and in such modifications of this structure illustrated and described as inay be equivalent to the claims.

In the drawings the same reference characters have been used to. indicate the same parts in 5 each of the various views.oi'which-'- Figure 1 shows a top or plan view partly diagrammatic, of an automobile chassis, in which the steering and braking mechanism incorporates the invention. Certain wellknown chassis portionsj not necessary to an understanding of this invention have been omitted.

. Figure 2 is a left side view or elevation of the same chassis.

Figure 3 is a vertical section through the 15, lower portion of the steeringshaft taken along. line 3-4 or Fig. 1.

Figure. 4 is a section-along line 4-4 of Fig. 3.-

Figure 5 is a sectional view takenin the plane indicated at [-5 in Fig. 3 7 20 Figures 6, .7 and 8 are partial sections along radial lines [-4, 1l, and M respectively of Fig. 5f

Figure 9 is a transverse vertical section through the brakeactuating rock shaft and'power relay 25 or driving wheels .l,=--and supporting a motoryor engine generally denoted as 5, connfectible to drive the driving wheelsi through the usual on mechanism generally denoted asia. Fig. 1. J

' Thefront wheels '2 may be manually shifted for steering purposes by any suitable For illustrative purposes such mechanism-- as vare controlled in the usual way. a

.Brakes may be manually operated on each of the drivingwheels 3 by any suitable mocha-' nism. By way of' example the drawings show 5 mechanism including a spring supported foot pedal or lever29 loosely connected for move- 'ment witha shaft'Zi supported from frame I.

Fixed with the respective rear wheels are brake drumsZZ within each of which operate brake shoes such as the shoes 24. The shoes of the different drums may be expanded in the usual way to grip the drums by means of rotatable or oscillating cam members 26 to which are attached levers 39 which are connected for movement from a shaft 2! by the means of similar levers 33 and link rods 35.

Since the foot pedal 29 is conveniently manually operable in only one direction, that is to say in the direction to apply the brakes, the other direction of movement in brake releasing .direction is brought about by a spring secured to the pedal 29and to fixed arm 42. A supplemental spring 4! acts similarly on the brake connections themselves through arm 33 on shaft 2|. i

This invention contemplates that neither of the direct actuating connections to" the steering wheels and brakes thus far described need be used normally but both are present for emergency use. In each case, however, power means is provided for control independently of the direct driving means and normally operative to the exclusion of the direct driving connections.

The power mechanism provided to shift the steering mechanism in accordance with the hand movement of wheel or handle 6 is as follows.

Fixed with worm 9 at the end thereof is a valve member generally denoted by the numeral 43 having an annular portion or ring 44, (Figs. 3, 5, 6, 7- and 8) within which is closely rotatably fitted a valve member which is rigidly fixed for rotation with steering shaft 1.

Also fixed rigidly upon worm 9 there is a gear 46, Figs. 3 and 4, meshed with which are rack teeth 41 on a plunger or piston 48 closely but slidably fitted in a bore 49 in a housing generally denoted by the numeral 59. The ends of bore 49 are-closed as shown in Fig. 4 to form cylinders within which the plunger 48 may be operated in the one direction by means of fluid supplied through a channel or pipe 52, Figs. 4 and 5, and in the other direction by the means of fluid supplied through a pipe or channel 53.

The members,44 and 45 are enclosed within housing 5| by means of a removable cover 54,

Fig/3, and together provide a, valve means in which the movement of member 45 in accordance with the movement of hand wheel 6 serves .to connect one or the other of the channels 52 or 53 with a fluid supply channel orpipe 56,

The member. is provided on its periphery .with annular grooves 58, 59, 69 and 6|, (Figs.

3, 6, 7 and 8) continuously communicating, respectively, with the exhaust channel 51, with the channel 52 leading to the right end (Fig. 4) of bore 49, with the channel 53 leading to the left 7 end (Fig. 4) '01 bore 49,. and with the supply channel '56.' On'. its inside surface the member 63, 64,(Figs. 5, 6, 7 and 8) continuously communicating, respectively; with the supplyigroove Bithrough a channel 65, (Fig. 5).,'=with-gro0ve 59 andpipe 52 through a channel 66 (Fig. 7) a.nd

53 with exhaust pipe orwith groove 69 and pipe 53 through a channel 61, Fig. 6.

The arrangement of annular grooves provide a means for maintaining the power supply lines in communication with respective ports in all rotative positions of the parts.

Axially extended grooves 68, 69 and i9, Figs. 3, 5, 6, and 7 in the peripheral surface of member 45 are constructed to provide cut away portions leaving land portions H, 12, Fig. 5, which in the normal position of valve 45 close both grooves 63 and 64, but in case the member 45 is slightly rotated relative to member 44 in the one direction the supply groove 62 will communicate with groove 63, and if the rotation is in the other direction the supply groove 62 will communicate with groove 64. At the same time the one of grooves 63 and 64 which is not in communication with groove 62 is uncovered to communicate with the one of the'grooves 69 and Ill each of which is continuouslyin communication with the exhaust, there being for each groove 69 and 19 a channel communicating with the annular'exhaust groove 58. Such communication is illustrated for the groove 69 in Fig. 8, by the means of channel 13, but the communication of groove 19, being exactly similar, it not shown.

To permit such relative rotational displacement of the members 44 and 45, the worm 9 with which member 44 is fixed, is slightly loose in its splined connection withsteering shaft 7 upon which member 45 is rigidly fixed. Such looseness or lost motion is in the present instance accomplished by providing some space between the key .74 and the sides of the complementary spline groove in pinion 46 as shown in exaggerated de-,

gree at '15 and 16, Fig. 4. The looseness or lost motion is such as to permit the steering shaft and member 45 to move slightly in either direction from the position in which both grooves 63 and 64 are closed from supply groove 62, whereby to admit fluid through the various channels to cylinder .bore 49 before the splined connection of shaft 1 and worm 9 causes worm 9 to move. The direction in which fluid is admitted to cylinder bore 49' is always such as to move plunger 46, gear 46, and worm. 9 in the same direction in which this assembly would be moved later by the key connection with shaft '1, but, provided fluid under pressure is continuously supplied to .the channel 56 the worm 9 will never be moved shaft as long as the wheel and shaft continue to move, but whenthe wheel movement stops or immediately thereafter, the valve cuts the cylinder 49 ofi from the fluid supply, and movement of r the worm also stops. lithe fluid supply for any reason should fail or if the fluid pressure should be inadequate for the resistance encountered the worm may still be moved or assisted in its movement by the manual power applied through key 14, the hand-wheel 6 being substantially similarly moved in either event. 44 is provided with axially extended grooves 62,

group 19, Fig. 5, is positioned on the opposite side of the axis of shaft 1, the two groups forming'an opposed-or balanced pair operative substantially ations the power mechanism. will follow the to balance any pressure tending to increase the frictional resistance between the members 44 and 45 of valve 55. The second group of parts is also desirableas permitting fluid to be admitted more quickly to the cylinder 49. Forthe same reason still other similar groups of parts may be arranged about the axis of member 44, preferably in balanced pairs.

Owing to the axial length of the grooves forming the'ports and to the several groups of similarly acting ports the lost motion required at 15 and 16 need be relatively very small in amount while still permitting a suflicient port area for worm 9 to follow a very rapid movement of hand wheel 6.' Additional axial length of individual ports or an additional number of ports may be The same lost motion which prevents the steering shaft from directly operating upon the worm controls the application of power to the worm, it being important to note that the power is applied to the worm itself so that steering takes effect throughth usual irreversible connections, just as in hand steering. Y

Thelimited independent movement of. shaft I with respect to the worm in either direction, displaces the valve member 45 with respect to its .complementary valve member 43 ions. suiilcient distance to establish communication to that end of cylinder H which will occasion a movement of piston 48 and worm 9 in the identical direction in "which the hand movement of shaft 1 has been initiated. As above noted, the piston It acts directly'upon the worm itself, the entire apparatus being assembled in a single unit.

The power applied, through the'fiuid pressureacting on piston 48 in cylinder 49 moves the worm for a distance corresponding to the distance to which shaft 1 and valve member 45 have been moved. The complementary valve member 3, being connected with the worm, ultimately reaches its'originalrlocation withrespect to valve member 45,-thereby cutting off all flow of liquid] to the cylinder lfl and restoring the balance of the parts. From this new position the parts may again be moved in either direction by initiating movement in the steering shaft 1, thereby displacing valve member 45 with respect. to'v'alve memberv l3 andest'ablishing communication between the source of power and the cylinder 48.-

a As above noted, the duplication of the series'of ducts 'll by a similarseries l8, and'the elongation of the which register upon relative 'displacement ofyalve member 45, are such asto give a very speedy response of the power (75.5mm mechanism. Thus, in all ordinary steering opermovement of the hand wheel just as rapidly as the hand wheel can be turned. It is only when there isa power failure that the key 14 is ever eii'ective to transmit motion from shaft I directly to the worm 8.

Power mechanism is provided as follows to shift the brakes in accordancewith the movement of the operator'shandl which for convenience is illustratedflas comprising the accustomed foot pedal 20: a

* pedal ll is fixed on the extended hub I9, Fig. 10, of a valve member 80 enclosed within a housing 8| and having an annular portion or ring 82 within which is closely rotatably fitted a valve member 83 which is rigidly fixed for rotation with the shaft 2|. Also fixed on the hub 19 of member 8! is a gear or segment 84 (Fig.9) meshed with which are rack teeth-l5 on a plunger or piston 86 closely butslidably fitted in a bore 81 in the housing ll. The ends of bore 81 are closed as in bore 49 (Fig. 4) whereby to form a cylinder within which the plunger 86 may be operated in the one direction by the means of fluid supplied through a channel or pipe 9| (Fig. 9), or in the other direction by the means of fluid supplied through a pipe or channel 92. These pipes cor: respond with pipes-52 and 53 (Fig. 4).

. The members 82 and 83 together provide a valve means operative in accordance with the movement of foot pedal 20 to connect one or the other of the channels 9| and 92- with a fluid supply channel or pipe 94 (Fig. 10) and to simultaneously.

connect the other. channel with an exhaust or outlet pipe or channel 95. The arrangement of channels or ports within valve 93 for such result may be identical with the previously described valve (Figs. 3 and 5 to 8) and includes peripheral grooves as, 91, as and as. (Fig. 9) in member a: and respectively continuously communicating by the means ofsuitable channels in the casing ;8l,

with the exhaust channel 95, with the channel 9!, with the channel 92 and with the supply channel 84.

There are also, as in the valve first described,

axially extended channels or grooves in the inside surface of member 82, respectively con-- tinuously communicating by the means of, suit,

able channels through member 82, with the exterior annular channels which communicate with the' channel 9|, supply channel 94 and channel 02. One of these is shown at 1.2 in Fig. I.

There are'also, as in the steering control valve, axially extendedw channels in the periphery of member 83, forming cut away portions and lands adapted normally to close the supply from both endsof the cylinder 93 but adapted to provide communicationto the proper end of plunger 86 in case the member 82 is rotated slightly. One such channel is shown at I05 in Fig. 9.

The whole arrangement corresponds exactly with that used for steering, in thatthe driven member is actuated by power in the same direction as the driving member would actuate it if positively connected thereto. The. positive connection is always potentially present butis ineffective the power operation fails dur ing-the degree of lost motion provided.

To permit such relative rotational displace ment between members 82 and '83 as 'isrequired to set the power actuating mechanism in operation, the key 106 (Fig. 10) which restrains member 8 to move with shaft 2| on which member 83 is fixed, is provided with lost motion exactly similar to the lost motion previously described for the similarly acting key 14. The degree of lost mo tion required is exaggerated in the drawings.

The various grooves and channels effective between members 82 and 83 to control the fluid as described, constitute a group of parts or controls generally denoted by the numeral I01 (Fig. 9).

Another similar control group I08, is positioned on the opposite side of the axis of shaft 2I for reasons pointed out forithe similar pair of ports of the steering control valve and still other pairs may be added if desired, for reasons explained. The effect of the arrangement including valve 83 and cylinder is that in eitherdirection of movement of foot lever 20 the shaft 2I and the brakes with which it is connected, will be forced returns shaft 2I and the parts connected therewith to a position corresponding to the released position of the brakes. It is to be noted that as the shaft 2I'is turned by the spring 4| the valve 80 normally acts to prevent the brake con-. nections from over running the foot lever, irrespective of key I06, such action being merely the reverse of the action previouslyv described. The function of the mechanism described is to prevent or correct by power, any displacement between two members thereof.

The operation of the brake applying mechanism is essentially similar to the operation 01' the steering mechanism as above described. In

I each case a limited degree of lost motion in the direct manually operable connections is provided to control the application of power, the, direct manual connection being always available in the event of a power failure.

For-supplying fluid to the channels 56 and 94 there'is provided the following mechanism: I

Fixed on the'crankshaft IIO, Fig. 1, of engine 5, is a gear III, which may be a gear used for one of the essential functions of the engine such as driving the cam shaft, but in any case should be operative whenever the engine is running, that is to say. irrespective of the position ofthe usual motion interrupting clutch mechanism generally, denoted at 511, Fig. 2, and irrespective of the position of the transmission or rate change mechanism of 'the vehicle, generally denoted at 5b, Fig. 1, and operated from the hand lever 5c Driven from the gear III is a gear III, Fig; 1 fixed on the driving shaft of. a pump, generally," denoted by the numeral II3, and which'may of any positive delivery type. Fixed with the engine is a unitary mechanism generally denoted. by the numeral II, (Fig. 1). Unit II4 provides a casing, or housing II5 (Figs. 1 andll) fixed with the engine frame and a cylinder II6 within casing H5, and in which is closely fitted a. piston I I1 continuously urged by a spring H8. The closed end II! of cylinder H6 is in communication with the outlet or pressure port of pump II3 by the means of a channel or pipe I20 whereby fluid delivered from the pump is delivered to the cylinder to move the piston II'I against the resistanee of spring H8 until a shank or stop I2I fixed with the piston contacts a cover I22. The

or channel m, rigs. 1 and 11, a cut oil throttle generally denoted as-I25, and a pipe or channel I26 extending below the fluid level.

The cut off throttle I25 consists of a cylinder I21 Fig. llwithin which a piston or plunger I30 is closely fitted. Cylinder I2! is closed by the means of a cap I32 and any fluid pressure set up by pump II3 tends to move the piston I30 against the pressure of a spring I33, there being a channel I34 delivering fluid from the pressure channel I20 to act against the piston end. The piston I30 is provided with a passage or port opening I35, which for anynormal premure within chan nel I20 provides a free passage between channels I26 and I2 4 whereby fluid may be drawn from the reservoir to the pump, but after piston I" has been moved by such fluid until stop I2I contacts cover I22 the pressure in channel I20 and against piston I30 rises to a value which moves the piston I30 against the resistance of spring I33 until passage I35 is outof registrywith channels I26 and I24, and no more fluid is pumped until the pressure in channel I20 drops sufliciently for spring I33 to ,move the piston for channel I35 to cause communication between channels 124 and 12s.

The cylinder H6 and piston I" provide an accumulator or storage device for fluid under pressure and which is generally denoted by the numeral I36, Fig. 11. Such accumulator is continuously maintained substantially filled with fluid by the means of the pump II3 whichruns continuously, whenever the engine is .running,

but is prevented from pumping any fluid except just sufficient to maintain the fluid in the accumulator by the means of the out 01f throttle I25.

Such construction provides that, although pump H3 is of positive delivery type and continuously running, there, is substantially no power con-:

sumed except that required to pump the fluid volume actuallyused, and for this, and other reasons, the arrangement is much preferable to accumulators charged from a pump which is continuously pumping a positive volume andin which the surplus fluid is being passed through a relief valve.

Accumulator I 36 is used as a continuously available supply source for both the fluid'operated devices previously described, there being a channel or pipe I31, (Figs. 1 and 11) communicating from the pressure channel I20 to the supphg channels 56 and 94, (Figs. 1,' 5 and 9) of the respective devices. The exhaust or outlet channel 51 (Fig. 5) and channel (Fig. 9) of the respective devices, each herein illustrated and, described is illustrative of agreat variety of mechanisms generally characterized by the fact that a relatively weak force operating to move a governing element may release and controls. force as largehs may be desired for the movement of a driven part in substantial accord both as to rate and direction of movement with the movement of the governing element.

Iclaimz' 1. In a control device, the combination with a her for a limited movement independently thereof and adapted with a predetermined degree of lost motion for the actuation of 'the driven member in either direction, means for applying power for the direct actuation of the driven member in either direction, and means operable by the movement of the manually operable member respecting the driven member within said range of lost motion to control the application of said power to the driven member in a direction corresponding to that in which the driven member will ultimately be actuated by the manually operable member if'the limit of lost motion between said members is reached, together with substantially irreversible motion transmitting connections leading from said driven member for the delivery of the power of said control device.

2. A control device comprising the combination with a manually rotatable driving member, of, a co-axially rotatable driven member loosely keyed to the driving member, casing means provided with bearing supports for the. shaft and member, mutually co-operative valve elements connected with the respective members and provided with ports registerable upon the relative movement of said members respecting each other within the range permitted by the lost motion of said key, fluid supply means leading to said valve elements, a plunger reciprocable in said casing provided with rack teeth, said casing having a cylinder bore at each end of the plunger ducts affording communication between said valve elements and the respective cylinder bores, and pinion teeth connected with the driven member and meshing with the rack teeth of said plunger.

3. In a control device, the combination with a driving control member and a driven control member, of a lost motion connection directly between said members for the direct operation of one by the other following a predetermined relative movement, a plunger acting upon the same member as said lost motion connection, a cylin- 'der in which said plunger is reciprocable, a source of fluid under pressure, and valve means controlled by a relative movement between said members for applying fluid from said source to said piston in a direction to operate the'driven member in advance of its operation through said lost motion connections, said driven member having an operating part and worm and worm gear connections thereto adapted to be moved thereby alike whether, said driven member is actuated by fluid pressure or through said lost motion connections.

4. In a steering gear, the combination with a steering shaft, a steering worm, and a rock shaft arranged to be operated by said worm, of a direct lost motion connection between said shaft and worm for the manual operation of the worm in theevent of power failure, power operated means for acting directly upon said worm, and means controlled by lostmotion between said worm and shaft for applying power through said means for the rotation of said worm in the direction and to the extent of shaft rotation, whereby steering motion is transmitted to said rock shaft in the same manner whether said worm is operated by alternatively available for acting directly upon.

said gear within said casing either by hand or by power to cause rotation thereof, the hand operating means comprising a shaft loosely keyed to said worm and the power operating means comprising a piston mechanically connected to rotate said worm in either direction according to the direction of piston reciprocation, a cylinder in which said piston is operable, fluid pressure ducts leading to the ends of said cylinder, and a control valve including, parts respectively connected with said shaftand with said gear and adapted upon occurrence of relative movement between said shaft and gear, and within the limits of said lost motion connection, to control a pressure difierential between the ends of said cylinder such as to move the gear in anticipation of the movement which would otherwise be occasioned therein through said l'ost motion connection.

4 Y FRED A. PARSONS. 

